Comparative proteomic and lipidomic analysis of yak and bovine buttermilk fat globule membranes: Insights into nutritional and functional differences

Yak buttermilk, a rare dairy source derived from highly nutritious milk, contains abundant functional components critical for protecting human health. Using label-free quantitative proteomics, 445 proteins in yak milk fat globule membrane were identified, notably, the proteomic analysis revealed that 232 proteins were uniquely expressed in yak milk compared to bovine milk. Among these, 16 MFGM proteins were significantly upregulated, suggesting potential functional implications for yak milk's distinct biological properties. These differentially expressed proteins participate in diverse biological processes and cellular components, primarily contributing to structural promotion of ribosomes, RNA binding, and catalytic activity. Notably, the MFGM lipids of yak buttermilk exhibit higher levels of phosphatidylcholine and phosphatidylethanolamine accounted for 32.47 % and 30.21 % respectively, and their contents were significantly higher than those of milk. • 232 unique MFGM proteins in yak buttermilk identified vs. bovine milk. • Yak MFGM lipids: PC (32.47 %) & PE (30.21 %) dominate, significantly higher than bovine. • Yak MFGM proteins primarily function in translation and ribosome structure/RNA binding. • Yak MFGM exhibits superior bioactive potential, linked to its unique high-altitude environment.